🎗️Longer Breastfeeding, Fewer ADHD Symptoms In Childhood

Does longer breastfeeding mean fewer ADHD symptoms? In a study of over 37,000 children, each additional month of breastfeeding was associated with a small reduction in symptoms of attention deficit hyperactivity disorder, even after researchers considered genetics, pregnancy conditions, and family factors.

Attention deficit hyperactivity disorder is a neurodevelopmental condition that can cause inattention, impulsivity, and hyperactivity. Genetics plays an important role, but factors present during pregnancy and the first years of life can also influence the development of these symptoms.

Since breast milk contains nutrients and other substances important for brain development, researchers wanted to investigate whether the duration of breastfeeding could be related to the intensity of ADHD symptoms during childhood.

To do this, they used information from 37,643 children born in Norway between 1999 and 2009. The data came from a large study that follows mothers, fathers, and their children from pregnancy onwards.

The researchers checked, when the children were six months old, how long they had been exclusively breastfed, that is, receiving mainly or only breast milk, without solid foods or other liquids. Then, they followed the children and assessed their symptoms of attention deficit hyperactivity disorder at 3, 5, and 8 years of age.

The assessment of symptoms was conducted through questionnaires completed by the parents. Instead of simply analyzing whether or not the child had a diagnosis, the researchers observed the quantity and intensity of the symptoms.

This is important because characteristics such as difficulty concentrating, impulsivity, and hyperactivity exist in varying degrees in the population. A child may exhibit some of these behaviors without necessarily having a diagnosis of attention deficit hyperactivity disorder (ADHD).

One of the main challenges was to determine if the association could truly be related to breastfeeding or if it could be explained by other characteristics. For example, mothers who breastfeed for longer may have differences in education, economic conditions, health, or other behaviors that also influence child development.

To address this, the researchers adjusted the analyses taking into account social factors, characteristics of gestation and birth, and genetic predisposition to ADHD. They assessed this predisposition in both the child and the parents, using genetic information to estimate the extent to which each participant had a hereditary tendency to exhibit the symptoms.

The researchers also conducted additional analyses to test whether the results persisted when considering potential problems with the study itself, such as children who were no longer followed up. In another analysis, they compared siblings from the same family who had different breastfeeding experiences. This comparison is interesting because siblings share a large part of their genetics and many characteristics of their family environment. Even after these analyses, the association remained.

The results showed that each additional month of exclusive breastfeeding was associated with a small reduction in symptoms of attention deficit hyperactivity disorder. The association appeared at ages 3, 5, and 8, although it was slightly smaller as age increased.

The researchers found similar results when they separated the children into those who received only breast milk and those who received breast milk along with other foods.

This means that breastfeeding may offer some protective effect against the symptoms of attention deficit hyperactivity disorder (ADHD), but the study does not prove that breastfeeding for a longer period causes this reduction. Genetics remains one of the main factors involved in the disorder, and many other aspects of the child's life also participate in this process.

It is not yet known exactly how breast milk could influence these symptoms. Important nutrients for brain development, components that influence the immune system, and gut-brain communication are some of the possibilities that need to be investigated.

The main result of the study is, therefore, a consistent association between longer breastfeeding duration and lower intensity of ADHD symptoms during childhood.

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Breastfeeding and Development of Attention-Deficit/Hyperactivity Disorder Symptoms Across Childhood

Berit Skretting Solberg, Anne Lise Brantsæter, Liv Grimstvedt Kvalvik, Catharina A. Hartman, Tian Xie, Kari Klungsøyr, Lin Li, Henrik Larsson, Rolf Gjestad, and Jan Haavik

Biological Psychiatry. 19 June 2026DOI: 10.1016/j.biopsych.2026.06.009

Abstract: 

Studies suggest that breastfeeding may be associated with a reduced risk of childhood attention-deficit/hyperactivity disorder (ADHD). However, determining causality is challenging because potential confounders, including genetic predisposition, may influence this relationship. We prospectively examined the relationship between full (exclusive or predominant) breastfeeding duration and ADHD symptoms in children, accounting for sociodemographic and perinatal factors and polygenic risk of ADHD. We obtained data from 37,643 children (49.1% girls) born from 1999 to 2009 and 18,349 mother-father-child units from the MoBa (Norwegian Mother, Father and Child Cohort Study). We examined the effect of full breastfeeding per month (self-reported when the child was 6 months of age) on parent-rated ADHD symptoms in offspring at 3, 5, and 8 years (multivariate regression models). Measures are expressed as unstandardized regression coefficients (B) with 95% CIs, adjusting for socioeconomic and perinatal factors and ADHD polygenic scores in child, mother, and father. Full breastfeeding per month was significantly associated with lower ADHD symptom scores at all ages (adjusted Bage3 = −0.08 [95% CI, −0.09 to −0.07], Bage5 = −0.07 [95% CI, −0.08 to −0.06], Bage8 = −0.06 [95% CI, −0.07 to −0.05]), indicating that each month of full breastfeeding associated with lower ADHD symptoms. Similar results were observed when we modeled breastfeeding as a categorical variable including both full and partial breastfeeding. Inverse probability weighting, accounting for loss to follow-up, and sibling analyses with discordant breastfeeding exposures, accounting for unmeasured confounding, supported the main results. Our findings suggest that full breastfeeding could partially protect against childhood ADHD symptoms. Further studies are needed to understand the potential mechanisms of the association between breastfeeding and lower ADHD symptoms.